@inbook{ea27132c9eb3443b8d8345e8a8b73c6e,
title = "ENSO Low-Frequency Modulation and Mean State Interactions",
abstract = "Is El Ni{\~n}o changing with global warming? Can we anticipate decades with extreme El Ni{\~n}o events? To answer these questions confidently, we need to understand the modulation of the El Ni{\~n}o Southern Oscillation phenomenon (ENSO) that occur on decadal and multidecadal timescales and involve changes in El Ni{\~n}o amplitude, periodicity, dominant “flavors”, shifts in the Intertropical Convergence Zone, and other properties. As major progress has been made in understanding various factors that can affect these characteristics of El Ni{\~n}o, two main paradigms have emerged to explain the observed modulation of ENSO: (i) internally generated variations due to the chaotic nature of the ocean-atmosphere coupled system and (ii) externally driven variations due to cyclic or secular changes in the properties of the tropical background state such as mean winds or ocean thermocline depth. This article reviews these two paradigms in the context of available observations, idealized models, and comprehensive general circulation models describing El Ni{\~n}o. Which paradigm will domi-nate in the coming decades and whether global warming is already affecting El Ni{\~n}o remains unclear.",
author = "Fedorov, \{Alexey V.\} and Shineng Hu and Wittenberg, \{Andrew T.\} and Levine, \{Aaron F.Z.\} and Clara Deser",
note = "Publisher Copyright: {\textcopyright} 2021 American Geophysical Union. Published 2021 by John Wiley \& Sons, Inc.",
year = "2020",
doi = "10.1002/9781119548164.ch8",
language = "English",
series = "Geophysical Monograph Series",
publisher = "John Wiley and Sons Inc.",
pages = "173--198",
booktitle = "Geophysical Monograph Series",
address = "United States",
}